Reciprocating internal combustion (IC) engines are known for converting chemical energy, stored in a fuel supply, into mechanical shaft power. A fuel-oxidizer mixture is received in a variable volume to an IC engine defined by a piston translating within a cylinder bore. The fuel-oxidizer mixture burns inside the variable volume to convert chemical energy from the mixture into heat. In turn, expansion of the combustion products within the variable volume performs work on the piston, which may be transferred to an output shaft of the IC engine.
Combustion engines may inject high pressure liquid fuel directly into the variable volume, and a liquid fuel delivery system may employ two or more fuel pumping stages in series to achieve the desired final injection pressure. For example, unit pump fuel systems for direct injection compression ignition engines may include a fuel transfer pump that draws fuel from a fuel tank and delivers the fuel to the inlet of a unit pump driven by a cam or hydraulic piston, for example, to further increase the fuel pressure to the desired injection pressure.
The evolution of diesel fuel injection systems has involved ever increasing injection pressures. As pressures increase, the wear of the high pressure fuel systems (HPFS) increases exponentially. To address this wear new filtration strategies may be developed to ensure that the low pressure fuel system (LPFS) provides very clean fuel to the HPFS. Any time the LPFS is opened (e.g., initial system build, filter change or system repair, etc.), dirt and debris may be introduced into the system, which can compromise the durability of the HPFS.
International patent application publication No. WO2011/004740 purports to describe a dimethyl ether (DME) fuel supply method in which a target supply amount of DME is supplied into a fuel tank of an engine through a fuel supply line. In the DME fuel supply method, the fuel supply line is opened, thereafter, a pressure difference is monitored. When the pressure difference is below a predetermined set value, a purging electromagnetic valve (RV-2) for the fuel tank is opened. When the pressure difference is above the predetermined set value, the purging electromagnetic valve (RV-2) is closed. The purging method of WO2011/004740 is triggered on a pressure measurement below specification and does not address the filtration of dirt and debris.
One strategy used to mitigate contamination by dirt/debris is to install a “last chance” filter right before fluid enters the HPFS. However, even this filter can introduce debris when the filter is removed from the system for replacement. Furthermore, determination of filter clogging may be difficult.
German patent application publication No. DE19828933 purports to describe a conventional system consisting of a fuel pump with a suction and a delivery filter. A monitor measures the potential of the positive lead to the pump, which is proportional to its power demand. The changing power demand, at the various levels at which the engine works, is then an analogue of the state of the filters so that a warning light on the dashboard can be lit when a predetermined limit is exceeded. However, the varying pressure of a HPFS may mask the correlation between power demand and an actual state of the filter. As such, these and other shortcomings of the prior art are addressed by the present disclosure.
It will be appreciated that this background description has been created to aid the reader, and is not to be taken as a concession that any of the indicated problems were themselves known in the art.